An ecosystem wiped out in a single generation

Coral reefs – among the world's most exciting habitats – are set for extinction. For the first time in history, humans will have destroyed not just a species but a whole living ecosystem.

Mankind stands on the brink of a bleak environmental first. The list of species extinct because of human action grows longer every day – but never before has humanity succeeded in wiping out an entire natural ecosystem.

Now, says one of the world's top oceanographers, that is exactly what is about to happen. Within a single human generation, every single coral reef on the planet will have been destroyed – a manmade environmental catastrophe on a scale never before seen.

This dramatic prediction was made by Professor Peter Sale, a senior oceanographer for the United Nations, who has been studying coral for more than 20 years. There is a lot to study: coral reefs provide habitats for thousands of species, representing fully 25% of all marine life. Great branching structures – built by billions of tiny coral organisms – rise off the seafloor like underwater skyscrapers, oceanic cities teeming with life and colour.

This biological richness is hugely important for the health of the oceans, and for humans too. It is estimated that as many as 1 billion people are supported, directly or indirectly, by coral reefs. Millions make a living on them from fishing or tourism.

But despite their bold and lively appearance, coral reefs are deceptively fragile. Professor Sale remembers a horrifying moment back in 1998: he was studying coral in the Seychelles when all of a sudden the reefs began to die.

Within a matter of weeks, 90% of the coral in the area was white and dead – a bleached desert where once there had been a riot of colourful diversity.

Further – and worse – 'mass bleachings' have followed. Fully a quarter of the world's coral is now severely threatened, the rest not far behind. Nor will it be easy to prevent the disaster. It is global warming that is killing the coral, along with ocean acidification caused by excess carbon dioxide (CO2) in the atmosphere. Efforts to reduce human CO2 emissions are under way, but, says Professor Sale, by the time we get global warming under control it will already be too late.

Kings of the world

Sale's book is called Our Dying Planet* – and there are many who share his pessimism. The death of coral, they argue, is just the latest environmental crime perpetrated by the human race. If Earth is like a huge organism, say some environmentalists, humans are like a terrible planetary disease, destroying every ecosystem they touch.

This is the opposite of the traditional view, expressed in the Bible and other sacred texts, that ultimately the purpose of the Earth is to sustain and support human life. To lose an ecosystem is sad, it might be argued, but in the end human needs must come first.

* Our Dying Planet, by Professor Peter Sale – published by University of California Press, 12th Sep 2011

You Decide

  1. What is more important – human prosperity or the health of the environment?
  2. Does it make sense to call humans a 'planetary disease'?


  1. Corals can be visually amazing. Create a coral-inspired artwork.
  2. Do some further research into coral reefs – then create a short presentation either on your own or in a group. Title: 'Why should we care about coral?'

Some People Say...

“The world would be a better place with no humans in it.”

What do you think?

Q & A

What exactly is a coral reef?
It's an extraordinary natural structure. At the heart of a reef are corals themselves, tiny soft organisms, called 'polyps' that grow in clusters in warm, shallow waters.
I thought coral was hard and rocky?
The amazing structures that people call coral aren't actually the coral organisms themselves. They are actually made of coral skeletons, piled up layer by layer with each new generation of polyps.
And why exactly are corals in trouble?
All sorts of reasons. The worst danger is from higher concentrations of carbonic acid in the oceans. Acidification is caused by high levels of atmospheric CO2, and it makes it much harder for corals to grow their skeletons.

Word Watch

The interconnected system that emerges from organisms interacting with each other and with their environment. Ecosystems tend to be very complex, and can be quite fragile.
Scientists who study the oceans.
Carbon dioxide is naturally a gas, but can dissolve in water to form carbonic acid. As the amount of CO2 in the air increases, so does the amount of carbonic acid in the oceans, a process known as acidification. About one quarter of CO2 emitted by human activity ends up as acid in the sea.
Traditional view
In a famous biblical passage, Genesis 1:28, God tells Adam and Eve: 'Be fruitful and increase in number; fill the earth and subdue it. Rule over the fish in the sea and the birds in the sky and over every living creature that moves on the ground.' This passage is taken by some Christians to indicate that humans have been put on Earth in order to rule it – or, perhaps, to care for it.

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